Explosive primer with actuating means

ABSTRACT

An elongated hammer overlies an explosive primer and a supporting member that extends laterally away from the primer, the end of the hammer remote from the primer being pivotally supported so that its opposite end can swing away from the primer against the resistance of a spring. The hammer and adjacent surface of the supporting member diverge toward the primer, and a spacer near the primer is disposed between the hammer and the supporting member where it normally spaces the hammer from that member. The spacer can be pulled toward the pivoted end of the hammer to swing the hammer away from the primer until the spacer enters an opening in the hammer, which permits the free end of the hammer to swing back and strike the primer.

United States Patent [191 Klasons et al.

[ Nov. 13, 1973 Primary Examiner-Benjamin A. Borchelt Assistant Examinerl-l. J. Tudor Att0rneyVictor A. Peckham [5 7] ABSTRACT An elongated hammer overlies an explosive primer and a supporting member that extends laterally away from the primer, the end of the hammer remote from the primer being pivotally supported so that its opposite end can swing away from the primer against the resistance of a spring. The hammer and adjacent surface of the supporting member diverge toward the primer, and a spacer near the primer is disposed between the hammer and the supporting member where it normally spaces the hammer from that member. The spacer can be pulled toward the pivoted end of the hammer to swing the hammer away from the primer until the spacer enters an opening in the hammer, which permits the free end of the hammer to swing back and strike the primer.

10 Claims, 8 Drawing Figures EXPLOSIVE PRIMER WITH ACTUATING MEANS [75] Inventors: Visvaldis Klasons; George Carroll Bowser, both of Baltimore, Md. [73] Assignee: Catalyst Research Corporation,

Baltimore, Md.

[22] Filed: July 10, 1972 [21] Appl. No.: 270,490

[52] US. Cl. 102/70 R, 89/1 B, 136/90 [51] Int. Cl. F421) 5/08, H04m 17/06 [58] Field of Search 102/70, 84, 65; 89/1 B; 136/90 [56] References Cited UNITED STATES PATENTS 2,454,528 11/1948 Temple 89/1 B 3,665,630 5/1972 Taylor 89/1 B 3,679,487 7/1972 Coyle 102/7OR 3,619,927 11/1971 RobineL. 89/1 B EXPLOSIVE PRIMER WITII ACTUATING MEANS Explosive primers are used in many different places for detonating explosives or igniting heat generating means, such as in thermal batteries. If a spring-pressed hammer that strikes the primer is normally disposed in a spring-relaxed position, then before the primer can be activated the hammer must be cocked and released. This usually requires two separate operations, but it also has been proposed that it be done with a single manual operation. However, the manner of accomplishing it has been more complicated and expensive than desired. On the other hand, if the normal position of the hammer is its cocked position, there is danger of accidentally releasing the hammer. Even if that does not happen, before the hammer is released the spring that presses against it may acquire a set so that when released the hammer fails to fire the primer.

It is among the objects of this invention to provide a device for activating a percussion primer, which is simple and inexpensive in construction, which is extremely safe, which requires but little space, which is dependable even though not operated for a long period of time, which permits a single movement by an operator to first cock and then immediately release the hammer, and which can be sealed in a housing if desired.

The invention is illustrated in the accompanying drawings, in which FIG. 1 is a plan view;

FIG. 2 is a longitudinal section taken on the line II-II of FIG. 1;

FIG. 3 is an end view;

FIG. 4 is a fragmentary side view showing the hammer fully retracted and about to be released;

FIG. 5 is a side view showing the hammer after striking the primer;

FIG. 6 is a fragmentary plan view of a modification;

FIG. 7 is a fragmentary side view of FIG. 6 showing the hammer at rest; and

FIG. 8 is a fragmentary central longitudinal section showing the hammer fully retracted and about to be released.

Referring to FIGS. 1, 2 and 3 of the drawings, a percussion primer 1 is connected to a supporting member that can be any device that requires a primer to activate it. For example, the supporting member may be the cylindrical casing 2 of a thermal battery, and it will be so described herein. One end of the battery is secured to a base plate 3 seated against a shoulder in a ring 4 that is screwed into a housing 5. At the opposite end the battery is provided with terminals 6 that project into openings 7 in the housing, where they can be connected to suitable wires. Secured to the inner surface of the base plate above the battery is a retaining plate 8 provided with a pair of vertically spaced horizontal slots 9 separated by an integral band 10 that is offset toward the primer.

An elongated hammer 12, preferably in the form of a metal strip, overlies the battery and the primer. One end of the hammer extends into the lower slot 9, where it is curved upwardly behind band 10 as shown in FIG. 2 to hold it in place while permitting the opposite free end of the hammer to swing up and down. The free end of the hammer is provided with a projection 13 on its bottom for striking the primer. The hammer is pressed toward the primer by means of a spring 14, but it is normally held out of contact with the primer by a spacer,

such as a short cylindrical member 15, disposed between the hammer and the battery near the primer. The hammer is inclined from its pivoted end upwardly across spacer 15 toward its opposite end so that the hammer and adjacent surface of the battery diverge toward the primer. The spring may be formed from a length of spring wire that is bent to provide a short central portion that extends across the top of the free end of the hammer. From there the spring extends along the opposite sides of the hammer, into the lower slot 9 and then upwardly past band 10 and out of the upper slot. The free ends of the wire engage the retaining plate 8 above its upper slot.

OPERATION In order to fire or activate the primer, the spacer member 15 is pulled quickly toward the pivoted end of the hammer. This is done most conveniently by a lanyard 17 connected to the spacer and extending toward the opposite end of the hammer and out through a hole 18 in base plate 3. The pivoted end portion of the hammer may be provided with a central longitudinal slot 19 to accommodate a portion of the lanyard. The outer end of the lanyard may be provided with a pull ring (not shown). As shown in FIG. 4-, when the spacer is pulled toward the pivoted end of the hammer, the spacer forces the free end of the hammer to swing upwardly away from the primer against the resistance of the spring. At a point near the pivoted end of the hammer, the spacer enters a recess or opening 20 in the hammer so that the hammer can then swing down and strike the primer without interference from the spacer, as shown in FIG. 5. Opening 20 can readily be provided by forming a reverse bend in the meta] strip that forms the hammer. Of course, the opening has to be deep enough to house the spacer when the hammer is in its lowest or primer-striking position.

It will be seen that by a single quick pull on the lanyard the hammer is first cocked and then released. In its uncocked or dormant position very little energy is stored in the spring. Energy is stored only during the brief time it takes to pull the spacer back along the hammer to the hammer recess 20. Therefore, the spring cannot take a set due to being kept under tension. The spacer 15 makes it impossible for the hammer to accidentally strike the primer. Activation requires positive action, a pull on the lanyard. The device also requires only a minimum of space and can be sealed in the housing if desired to exclude contaminants that could interfere with its operation.

In the modification shown in FIGS. 6, 7 and 8, the free end portion of a hammer is formed from an inclined flat plate-like member 25, from the opposite edges of which arms 26 extend in parallel relation back to a retaining plate 27 secured to the inner surface of a base plate 28 above a battery case 29 or other supporting member. At opposite sides of the hammer the retaining plate is provided with bifurcated lugs 31, through which pivot pins 32 extend. The inner ends of the pins project from the lugs and through openings in the adjoining ends of the hammer arms so that the hammer can swing toward and away from the primer. The hammer is urged toward a primer 33 by a spring 34 formed from a length of spring wire that is bent to provide a short central portion which extends across the top of the free end of the hammer. From this central portion the spring extends along the opposite sides of the hammer and the free ends of the wire extend upwardly through lugs 31, between pivot pins 32 and the retaining plate. The side portions of the spring may be provided with loops to increase its resiliency.

Although the spring tries to press the hammer toward the primer, the hammer normally is held out of contact with the primer by means of a spacer block 36 that is located between the hammer plate 25 and the battery near the primer, as shown in FIG. 7. Joined to the central portion of this block is the inner end of a rod 37 that extends back through openings in the retaining plate and the base and out through a bushing 38 secured to the base plate. The outer end of the rod may be provided with a pull ring 39.

To prevent the rear edge of the hammer plate from resting on the rod and thereby maintaining the spring under considerable tension all the time, the plate is provided with a central longitudinal slot 41 that extends from its rear edge to a point over the block'in its at-rest position as shown in FIG. 6. This slot is wide enough to permit the plate behind the block to straddle the rod, but the width of the spacer block is greater than the width of the slot so that the block cannot pass through the slot.

To activate the primer, the rod is simply pulled outwardly quickly, which pulls the spacer block back toward the retaining plate 27. As the block is retracted in this way, it slides along the inclined hammer plate and thereby swings the hammer farther away from the primer until the block reaches the rear edge of the plate as shown in FIG. 8. The moment the block passes that point, the hammer is free to be swung down against the primer by the spring because the block is now in the opening 42 between the retaining plate and the hammer plate and entirely out of engagemeht with the hammer.

According to the provisions of the patent statutes, we have explained the principle of our invention and have illustrated and described what we now consider to represent its best embodiment. However, we desire to have it understood that, within the scope of the appended claims, the invention may be practiced otherwise than as specifically illustrated and described.

We claim:

1. In combination, an explosive primer, a supporting member extending laterally away from the primer, an elongated hammer overlying said member and primer, means pivotally supporting the end of the hammer remote from the primer so that its opposite end can swing away from the primer, a spring urging said opposite end of the hammer toward'the primer, the hammer and adjacent surface of said supporting member diverging toward the primer, a spacer between the supporting member and hammer near the primer and normally spacing the hammer therefrom, and means connected to the spacer and extending past the pivoted end of the hammer for pulling the spacer toward that end to swing the hammer away from the primer, the hammer being provided near its pivoted end with an opening for receiving said spacer to permit the hammer to strike the primer when the spacer enters said openings.

2. In the combination recited in claim 1, said hammer being a metal strip provided with a reverse bend forming said opening.

3. In the combination recited in claim 1, said spacer being a cylinder and said pulling means being a lanyard.

4. In the combination recited in claim 1, said spacer being a block and said pulling means being a rod attached to the block.

5. In the combination recited in claim 1, said spacer being a block and said pulling means being a rod attached to the block, and said hammer being provided with a longitudinal slot receiving a portion of the rod while said block is near the primer.

6. In the combination recited in claim 1, said spacer being a block and said pulling means being a rod attached to the block, and the free end portion of said hammer including a plate-like member normally engaging said block and having an edge defining one end of said opening.

7. In the combination recited in claim 1, said spacer being a block and said pulling means being a rod attached to the block, and the free end portion of said hammer including a plate-like member normally engaging said block and having an edge defining one end of said opening, said plate-like member being provided with a longitudinal slot extending from said edge toward the primer for receiving a portion of the rod while said block is near the primer, the block being wider than said slot.

8. In the combination recited in claim 1, said spring being formed from a spring wire having a central portion extending across the hammer opposite the primer and having side portions extending along the opposite sides of the hammer toward its pivoted end, and means anchoring the opposite ends of said spring wire.

9. In the combination recited in claim 1, said spring being formed from a spring wire having a central portion extending across the hammer opposite the primer and having side portions extending along the opposite sides of the hammer toward its pivoted end, and means anchoring the opposite ends of said spring wire, said spacer being a ball and said pulling means being a lanyard.

10. In the combination recited in claim 1, said supporting member being a thermal battery and the primer being connected with the battery for activating it. 

1. In combination, an explosive primer, a supporting member extending laterally away from the primer, an elongated hammer overlying said member and primer, means pivotally supporting the end of the hammer remote from the primer so that its opposite end can swing away from the primer, a spring urging said opposite end of the hammer toward the primer, the hammer and adjacent surface of said supporting member diverging toward the primer, a spacer between the supporting member and hammer near the primer and normally spacing the hammer therefrom, and means connected to the spacer and extending past the pivoted end of the hammer for pulling the spacer toward that end to swing the hammer away from the primer, the hammer being provided near its pivoted end with an opening for receiving said spacer to permit the hammer to strike the primer when the spacer enters said openings.
 2. In the combination recited in claim 1, said hammer being a metal strip provided with a reverse bend forming said opening.
 3. In the combination recited in claim 1, said spacer being a cylinder and said pulling means being a lanyard.
 4. In the combination recited in claim 1, said spacer being a block and said pulling means being a rod attached to the block.
 5. In the combination recited in claim 1, said spacer being a block and said pulling means being a rod attached to the block, and said hammer being provided with a longitudinal slot receiving a portion of the rod while said block is near the primer.
 6. In the combination recited in claim 1, said spacer being a block and said pulling means being a rod attached to the block, and the free end portion of said hammer including a plate-like member normally engaging said block and having an edge defining one end of said opening.
 7. In the combination recited in claim 1, said spacer being a block and said pulling means being a rod attached to the block, and the free end portion of said hammer including a plate-like member normally engaging said block and having an edge defining one end of said opening, said plate-like member being provided with a longitudinal slot extending from said edge toward the primer for receiving a portion of the rod while said block is near the primer, the block being wider than said slot.
 8. In the combination recited in claim 1, said spring being formed from a spring wire having a central portion extending across the hammer opposite the primer and having side portions extending along the opposite sides of the hammer toward its pivoted end, and means anchoring the opposite ends of said spring wire.
 9. In the combination recited in claim 1, said spring being formed from a spring wire having a central portion extending across the hammer opposite the primer and having side portions extending along the opposite sides of the hammer toward its pivoted end, and means anchoring the opposite ends of said spring wire, said spacer being a ball and said pulling means being a lanyard.
 10. In the combination recited in claim 1, said supporting member being a thermal battery and the primer being connected with the battery for activating it. 